Analyzing Percent Iron(Iii) Composition of a Ferric Salt by Titration

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Analyzing Percent Iron(III) Composition of a Ferric Salt by Titration Discussion Part One: A titration is a volumetric technique in which a solution of known molarity and volume (a titrant) is added into a solution of unknown concentration but known volume (the analyte). The titrant, EDTA, was at a concentration of .02060 M and the analyte used was the ferric salt solution which was to be analyzed in order to determine its Fe(III) content. Percent composition was to be determined by performing a series of titrations. Five titrations were performed in order to obtain three which were close enough to each other to be deemed precise. The three endpoint values chosen were 15.84 mL, 15.91 mL, and 16.17 mL, leading to an average endpoint value 15.97 mL with a standard deviation of .17. The milimoles of Fe(III) titrated was .3289, corresponding to .01837g of Fe(III) in a total mass sample of .18417g. The salt sample was determined to be 9.976% Fe(III). Part Two: Since a well-trained technician is expected to perform a titration with a percent relative standard deviation below 1.0%, the performance of this titration would be deemed almost passable, but ultimately sub-par. The % RSD was 1.1% based on the three closest endpoint values. Having used all the values collected, the RSD would have certainly been much larger as the other two values were much larger than the three included in the average. An indicator is a substance that undergoes a change of color when the equivalence point of a titration is reached. It is useful to use an indicator in a titration because the indicator allows the experimenter to know when the equivalence point (which should signify the end of the titration) is reached. Without the indicator, the titration would not work because the person performing the titration would not know when to stop titrating. The indicator shows when enough

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